While mounting an individual terrorist attack costs relatively little, money remains of critical importance for terrorist organizations. Without it, terrorist groups would be incapable of maintaining the broad infrastructure necessary to run an effective organization. As such, finding means to quickly and securely raise, launder, transfer, store, and gain access to funds remains a top priority for all terrorist groups, from al-Qaeda and its various globally oriented affiliates to regionally focused groups like Hamas and Hizballah. Terrorist finance is also an area of rapid change, as terrorist organizations seek actively to evade governmental scrutiny and take advantage of emerging technologies. The shift in the nature of the global terrorist threat -- from a centralized al-Qaeda to a franchise model -- has had an impact on terrorist financing as well. Until the September 11 attacks, combating terrorist financing was not a strategic priority for the U.S. government. But in the wake of the attacks, the United States dramatically heightened its focus on combating terrorist financing, employing an aggressive, multifaceted response in which it designated and froze the assets of numerous terrorist financiers and support networks, prosecuted individuals and entities for providing material support, and increased its focus on "following the money" as a means of collecting financial intelligence. The U.S. government also made a variety of structural and organizational changes to better address this key concern. The United States was hardly alone in its new focus on terrorist financing: many other countries followed suit. The European Union established terrorist blacklists, among other actions, and a number of the Persian Gulf countries put regulatory regimes in place to govern this arena. The private sector's role -- and its importance -- in the global efforts to combat terrorist financing also increased. While the United States led the international charge on these issues, two international organizations, the United Nations and the Financial Action Task Force, also deserve credit for the scale of the global response since September 11. Despite this progress, a number of obstacles remain, handicapping international efforts to combat terrorist financing.